It was a typical summer afternoon line-up at the B.C. Ferries terminal at Tsawwassen. The announced delays were not welcome - but were far from unusual on the ferry service that travels between Vancouver, Vancouver Island and the smaller islands off the west coast.

But as passengers settled in to their cars and turned up their radios, they heard news that was new, unexpected and frightening - a bomb threat had shut down the service.

Passengers already loaded on departing vessels were ordered off and ferries that had left their berths turned back. For five hours, passengers were left stranded in the terminal.

Twenty-one sailings were cancelled and police searched more than 1,000 vehicles using bomb-sniffing dogs.

'You never expect to see something like this on B.C. Ferries,' said island resident Deborah Tolman as she waited in line. 'We use the ferries just like a road to go back and forth to the mainland. It's basic transportation for us.'

A frustrated B.C. Ferries president David Hahn offered a C$50,000 (HK$370,600) reward for information about the person who made the bomb threat, which was eventually determined to be a hoax.

Mr Hahn said the call had been traced to a pay phone in a suburban shopping centre, initially describing the caller as having a Middle Eastern accent.

Mr Thompson said he doubts the caller was serious or that even the accent was real. He is convinced the bomb threat was not the work of any disgruntled group. In Canada, the only serious terrorist threats are from Jihadists or animal rights activists. Jihadists aren't in the habit of placing warning calls and animal rights groups haven't yet targeted large groups of people at random, he said.

The hoax has exposed gaping holes in security for a system that carries 60,000 passengers daily. About one-third of those passengers travel on the most-popular Vancouver-Victoria route, which has up to 16 crossings daily. Passengers pay and board. There is no pre-screening and no passenger list.

From the political hub of Victoria, another ferry can take passengers onwards to Washington State where incoming travellers face a much different set of security requirements. Vehicles boarding the US-bound ferry are met with bomb-sniffing dogs and state patrolmen.

Washington State has good reason to be paranoid. On the eve of the new millennium, Ahmed Ressam used a forged Canadian passport to travel to Port Angeles, Washington, from Victoria carrying a trunk load of explosives.

The federal government has given B.C. Ferries about C$4 million to pay for upgrades, including new security measures that were put in place days after the latest bomb scare. More cameras have been put aboard vessels and terminal security has also been enhanced.

But for now, it doesn't appear as if B.C. Ferries is willing to take the step of screening all passengers, something the president of the corporation had said last spring he would put in place if there was a terrorist event.

The incident will certainly be discussed this autumn when the federal government begins consultations on whether to impose more stringent security on domestic ferries. It is not hard to envision a future in which B.C. ferry trips are more like air travel, and less like travelling the open highway.